Discriminating fuze



July 19, 1960 c. c. voGT 2,945,440

' DISCRIMINATING FuzE Filed Decc 16, 1949 4 Sheets-Sheet 1 R,libwww/tofu CHARLES @vom f 5/ i f I I 4 .20 f43 ,Vl 25 /9 July 19, 1960c. c. voGT 2,945,440

DISCRIMINATING FUZE Filed Dec. 16, 1949 4 Sheets-Sheet 2 40 35 CHARLESC. VOGT 'July l19, 1960 c. C. vom 2,945,440

DISCRIMINATING UZE Filed Dec. 16, 1949 4 Sheets-Sheet 3 Y O Or a@ f4,CHRLES c.voGT

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July 19, 1960 c. c. voGT 2,945,440

DISCRIMINATING FUZE Filed Dec. 16, 1949 4 Sheets-Sheet 4 Q-la7 CHARLESc. voGT 'www Patented July is, 1960 DISCRIMINATING FUZE Charles c. Vogt,720s Denton Road, Bethesda 14, Md. Filed Dec. 16, 1949, Ser. No. 133,451

1'1 Claims. (Cl. 102-16) (Granted under Title 35, Code (1952), sec. 266)This invention relates generally to fuzes and more particularly to fuzesof the discriminatingtype adapted for use in'an airborne underwaterground mine to selectively distinguish between the landing of the mineupon land or water and to effect the destruction of the mine should itfail to fall within -water of a predetermied depth.

Heretofore planes have been extensively employed to transport underwaterland mines to enemy waters whereupon the mines are released to bedirected into the water either by means of a tail iin structure or by aparachute attached generally to the after portion of the mine andadapted for being released therefrom by means of an inertia actuateddevice operable upon the mine striking the water to disengage theparachute therefrom allowing the mine to sink to the bed of the body ofWater and there await the approach of an enemy vessel.

Generally,` for strategic reasons, such mine planting operations areconducted during the hours of darkness and from planesy flying atconsiderable heights thereby greatly increasing the possibility of themine missing the target area to fall either upon land or in such shallowWater, or mud, as to permit its recovery by the enemy whereupon it maybe dismantled and its secret control mechanism analyzed andcountermining apparatus therefor accordingly devised.

In order to make a mine self-destructive should it, by chance, come 4torest, after release, upon land, or insuch shallow Water, or mud, as tobe discernable by the enemy, applicant has devised a new Yand improveddiscriminating fuze mechanism adapted to selectively distinguish betweenfavorable and unfavorable conditions of rest of the mine and,accordingly, in the case of the latter, to operate to detonate the mineor otherwise render it unserviceable to the enemy if recovered.

It is an object of the present invention to provide a new and improveddiscriminating fuze mechanism for use in airborne underwater groundmines adapted to selectively distinguish between conditions of rest ofthe mine, after the launching thereof, on land or in water of apredetermined depth, and in case of the former, or if the water does notexceed the predetermined depth, operate to effect the destruction of themine.

A further object is to provide a new` and improved discriminating fuzemechanism for use in a marine ground mine adapted for launching from aplane iiying above the surface of the water and wherein a powder trainignited as the mine strikes the water is broken by the submergence ofthe mine to a predetermined depth therein.

l. -A still further object is to provide a new and improveddiscriminating fuze for underwater ground mines adapted to be launchedfrom a plane flying above thesurface of the water and wherein the armingof the fuze is accomplishedby a predetermined rate of fall of the minefrom the plane after thereleasingof the mine therefrom.

An additional object of the present invention is to prounderwater groundmine wherein a section of the powder train of the fuze aligned as themine drops from the plane is broken by the submergence of the mine to apredetermined depth within a body of water.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following `detailed description when considered inconnection with the accompanying drawings wherein:

Fig. 1 is a View partly in elevation of the fuze mechanism of thepresent invention as arranged within an underwater ground mine of thetype adapted for launching fromY a plane flying above the surface of thewater;

Fig. 2 is an enlarged fragmentary view in section of the fuze mechanismwhen in unarmed position;

Fig. 3 is a View in section of the fuze mechanism as it would appearwhen submerged within a body of water of sufficient depth tohydraulically interrupt the burning ofjthe powder train therein;

' Fig. 4 is a plan view of the fuze mechanism in its initial or unarmedposition with the booster charge and vide a discriminating fuzemechanism for an air launched lower section-of the housing cut away;

Fig. 5 is a fragmentary sectional view 4taken along lines 5 5 of Fig. 4and showing the arming ring therein in its initial or unarmed position;

Fig. 6 is a view of the end of the primer and attaching bracket thereforas secured to the end of a supporting stud element of the fuze;

Fig. 7 is a view partly in section showing the first and auxiliarybooster arrangements within the fuze housing;

Fig. 8 is a schematic view of the circuit arrangement of the presentinvention;

Fig. 9 is a schematic IView of an alternate circuit arrangement of theinvention wherein an inertia generator is substituted for the batteryand inertia switch as shown in Fig. 8;

Fig. 10 is a fragmentary sectional view showing the arrangement of aclosing plug within an opening through which the arming wire isdischarged from the fuze; and

Fig. 11 is an alternate form of the invention wherein a planetary gearassembly is employed in the fuze and interposed between the clutch ringand arming ring therefor.

Referring now to the drawings and more particularly to Fig. 1 thereof,the fuze assembly of the present invention, generally designated 5, isshown as arranged within a conventional underwater ground mine of thetype adapted for launching from a plane ilying above the surface of thewater. Such mines are generally comprised of an outer casing 6 to whichis fastened as by a ring structure 7 a detachable parachute, or finnedtail structure 8 for maintaining the mine in a proper position oforientation as it descends through the air to Ithe surface of the water.

Positioned centrally of the mine case and with axis perpendicular to theaxis of the mine is a pair of cylindrical containers 9 and 10 within|which is disposed, but not shown, the pressure responsive or armingelements of the mine adapted to arm the mine as it descends through thewater. A tubular connection 11, arranged as illustrated, provides areceptacle for accommodating electrical connections from the armingelements of the mine tothe electronic controls therefor located' withina housing structure 12 centrally secured within the base end portion ofthe mine as by an annular plate member 13. A search coil 14, disposedlongitudinally'within-the mine case, operates responsive to theproximity of a vessel to the mine to produce an electric signal by4which the controls of the mine respond to detonate the explosive charge15 of the mine. Y 'i The fuze 5, Fig. 2, is comprisediof an annularchassis member 16 shown as secured by bolts 17 within an annular openingprovided therefor within an eye equipped mounting plate 18 forming apart of the mine casing and by which the mine is secured by the eyes 30to the release mechanism of the plane. A pair of ring gaskets 20 formedof rubber or the like and arranged, as illustrated, between the chassis,plate and fuze housing 21 provide the pressure sealing connectionbetween kthese respective members as attaching bolts 17 therethrough aretightened.

Secured as by screws 22, Fig. 4, to the inner face of the chassis is asubstantially U-shaped bracket member 23 within a leg 24 of which isprovided an elongated bore 25 threaded at 26 for receiving therein acorrespondingly threaded tubular fitting 29 adapted as the fitting isdrawn into the threaded end portion of the bore to press about theflange portion 28 of the fitting a gasket member 27 thereby to provide apressure sealing connection between the tting and the outer face of thechassis 16.

Threaded into the inner surface of the leg 24 is a pressure responsivebellows assembly generally designated 35 and including an annularclosing plate 36 wherein is provided a centrally arranged bore 37adapted as the plate is threaded at 38 into the leg of the bracket tointersect the bore 25 and thereby to establish a fluid circuit betweenthe inner chamber 40 of the bellows and the atmosphere or waterwhichever may be surrounding the mme.

Closing the end of the bellows 41 opposite the plate 36 is asubstantially cup shaped member 42 wherein is secured as by soldering,or the like, an extending shaft section 43 adapted, upon expansion ofthe bellows in response to a predetermined increase in pressure therein,to be moved axially within guide surfaces 44 and 45 provided therefor inthe body and leg members 46 and 47 respectively.

A spring 54 arranged about the shaft, as illustrated in Fig. 2, andinitially compressed between the leg 47 of the bracket 23 and anextending flange portion 48 of the shaft, is elfective to maintain, inthis manner, the bellows normally compressed, as illustrated in Fig. 2,with the inner surface of the cup 42 resting against the inner surfaceof the plate 36 and thereby, for a purpose to become more fully apparentas the description proceeds, to initially position a powder filledsection 49 in the shaft 43 within a powder train generally designated'50.

Arranged over the shaft 43 and adapted for rotation thereon is a reel 51whereupon is wound a length of small diameter wire 52 preferably of thestainless steel type. The outer, or free end 53 of the wire is arrangedthrough a small opening 73 provided therefor in a resilient member 55preferably cast within a concavely formed cup member 56 invertedlysecured by an extending ange portion 57 thereof to the outer face of thechassis as by bolts S. A gasket 59 arranged between the flange of thecup and chassis member 16 provides a pressure sealing connectiontherebetween as bolts 58 are tightened.

Disposed in an exterior recess 60 formed in the base of the cup member56 is an arming plug 61 to which is secured, as by brazing or the likeat 62, the end of the wire section 53, the plug having thereon anintegrally formed ring portion 64 to which a cable 65 is attachedwhereby the plug is secured to the plane carrying the mine to the placeof launching. As the mine is released from the plane, the cable 65 iseffective to withdraw the plug 61 from the recess 60 by shearing anarming wire 66 and thereby to withdraw the wire 52 from the reel at avelocity corresponding to the rate of descent of the mine from theplane. The wire 52 when drawn from the reel 51 in this manner iseffective to apply a high rate of rotation to the reel for apredetermined interval of time depending upon the length of wireemployed and thus to arm the fuze, as will become more fully apparent asthe description proceeds.

Secured as by lead solder, or the like, to the inner end of :the wire 52is a plug member 70 having thereon a 4 plurality of flange portions 71,Fig. l0, and initially retained, as the wire 52 is wound upon the reel,within a recess 72 provided therefor within the hub portion of the reel,as indicated in 2. The plug is adapted, as the last of the wire is drawnfrom the reel, to be carried by the wire into the opening 73 whereuponthe resilient member 55 expands to allow the plug to be drawn therein toAthe position indicated in Fig. 3 and there to become a pressure andwater-tight closure for the opening 73.

Diametrically disposed within an enlarged hub portion 75 of the reel area plurality of radial bores 76 wherein is respectively arrangedelongated plungers 77. About each of the plungers is provided a spring78 adapted by reason of a predetermined loading of the springs betweenan annular retaining ring 79 therefor and an extending flange portion 80of the plungers, to prevent outward movement of the plungers from thereel except under conditions of high acceleration as may be caused by apredetermined rate of rotation of the reel resulting from the rapidwithdrawing of the wire 52 therefrom. Inserts 81 of leather, or thelike, preferably cemented within recesses formed, but not shown, in theends of the plungers 77 are elfective, as the plungers are centrifugallyextended, to frictionally engage the inner surface of an arming ring 82whereby the ring is rotated by the reel to the armed position thereof,Fig. 7.

The arming ring 82 is initially maintained in an unarmed position, Fig.2, by pressure thereagainst of a spider spring 83 interposed betweenvthe ring and the base of a bore 84 formed in the body section 46 andwithin which the ring closely fits for rotation upon the shaft Vsection43 and freely within bore 84. The powder train 50 which is initiallybroken by the arming ring 82 when the latter is in safe position, Fig.2, is completed for arming the fuze by rotation of the arming ring, inthe manner described, to the armed position indicated in Fig. 7, thering having a diametrically arranged portion 99 of the powder trainwhich becomes aligned therewith as the ring moves to the armed position.

Extending inwardly from an edge of the body section 46, Fig. 4, is astud 8'7 about which is wound a selected length of delay element 88forming a part of the powder train 50. The element may be in the form ofa powder filled lead conduit having one end thereof secured as bycrimping Within the shell of an electroresponsive primer 90. The otherend of the element is adapted for being received within a bore 91provided therefor in the body member 46 for connecting with the section92 of the powder train as at 93. The primer is supported from the end ofstud 87 by a two Section clamping bracket 94, Fig. 6, secured about theprimer as by screws 89 and having arranged in the lower section thereofa set screw S5 adapted for `being drawn into engagement with the end ofthe stud whereby the bracketv and primer is secured thereto after theelement 88 has been properly arranged over the stud and the end of theelement inserted, as indicated, within the bore 91.

Secured to the periphery of the arming ring 82 is a stud 97 over whichis arranged a metallic sleeve 96 suitably insulated from the stud as byan insulating sleeve 95. The metallic sleeve 96 when carried by rotationof the ring 82 between the exible lingers 100 and 101 of an armingswitch 102 is effective to complete an electrical circuit from thedetonator 90 to an interia responsive switch 105 of the type shown anddescribed in the copending application of Bob Norris et al. for TorpedoExploder Mechanism, Serial No. 105,856, tiled June 20, 1949.

The booster 112 is confined within an elongated casing 113 preferablypressed lit within the body section 46 and adapted for extendingoutwardly therefrom and into a well portion 114 of a partition 120adapted to separate the mechanism of the fuze from a auxiliary boostercharge 116 arranged within the lower portion of the housing 21, asillustrated in Fig. 7. The partition is segeziene t s iired to thehousing in any suitable manner as by rolling therewith as at 115. Theauxiliary booster 116 is adapted when ignited by the booster 112 toexplode the mine or effect the destruction of the controls therefor byvigniting 4a charge 117 arranged in the base end portion of the controlhousing 12, Fig. l, and within which the section 119 of the charge 116extends.

The circuit arrangement of the present invention is shown in Fig. 8 toinclude the primer 90 adapted for being energized through a circuitincluding the battery 121 and the normally open inertia switch 105 andarming switch 102. The inertia switch 105 includes an inertia responsiveelement 122 centrally disposed within a globular contact member 123, theformer being adapted to engage the latter upon impact of the mine witheither land or water as the case may be. The arming of the mine by theclosing of the switch 102 is effected, as heretofore described, inresponse to the falling of the mine from the plane. .The connections124, 125, 126, and 127 are shown in Figs. 4 and 5 of the drawings asthey connect with their respective elements of the fuze.V

An alternate circuit arrangement is provided in Fig. 9 wherein aninertia responsive generator 130' is adapted to supply current forigniting the primer 90 in lieu of the battery 121 as shown in theprevious circuit. The inertia generator may be of any type suitable forthe' purpose such, for example, as the generator disclosed and claimedin the copending application of H. I. Plumley for Magnetic InertiaControlled Fuze, Serial No. 535,799, led May 16, 1944, now Patent No.2,775,941, and whereinv a magnetic circuit established by a permanentmagnet member 131 is closed by a keeper element 132 magneticallyretained in the position indicated against the poles of the magnet andadapted in response to shock t-o be disengaged from the magnet andthereby to interrupt the magnetic circuit maintained thereby to inducein a pair of wire coils 133 and 134 arranged on the magnet a voltagesutlicient for operating the primer 90 whereupon the primer is Vexplodedto effect the ignition of the powder train 50 in the manner heretoforedescribed.

Frequently it is desirable to arm the fuze only after the mine hasfallen a definite distance from theA plane following its releasetherefrom. Therefore, it is provided in an alternate arrangement of theinvention, as illustrated in Fig. 11, that a planetary gear assembly,generally designated 135, be interposed between a clutch ring 136 and anarming ring 137 whereby rotation of thetarming ring to a position forarming the mine is affected only after a predetermined number ofrotations of the clutch ring 136. The planetary gear assembly 135 iscomprised of a freely rotatable pinion 138 mounted upon a stud 139secured as by soldering to the rear face of the clutch ring 136. Thepinion 138 has teeth for loosely meshing with correspondingly formedteeth about the periphery of a pair of gears 140 and 141 secured to thearming ring. 137 and shaft section 43 respectively, the gear 141 havingarranged in the hubthereof a longitudinal slot 142 adapted for receivingtherein a pin 143 secured, 'as by press fitting, within the shaftsection 43 `whereby there is provided an arrangement suitable for`preventing rotation of the gear 141 yet allowing free longitudinalmovement of the shaft therethrough responsive to the expansion of thebellows 41. .The gear 140 may be either integrally formed as shown orseparately formed and secured as by silver soldering or the like, to theinner face of the arming ring 137 and arranged in face adjacency withgear 141, whereupon the idler pinion 138 is elfective to mesh with eachof the gears respectively. The gear 140 is provided with one or moreteeth than the gear 141 whereupon, as the idler pinion 138 is rotatedabout the periphery of the gears, the gear 140 is caused to4 rotate thearming ring 13:7` gradually to armed position similarly to the armedposition of ring 82 as indicated in Fig. 7. The particular safetyfeatures of this alternative form of the fuze reside in the -fact that dthe reel 51 must be rotating at a predetermined velocity before thecentrifugally responsive plungers 77 arranged therein will engage theclutch ring 136, as in the fuze of Fig. 5, and in the additional factthat the clutch ring will rotate the idler pinion 138 severalrevolutions about gears 140 and 141 prior to complete movement of thearming ring to the armed position. This arrangement provides that thespeed of rotation of the reel 51 must be maintained at, or in excess ofa minimum velocity for a predetermined interval of time continuouslyuntil such time as the gear 140 lhas stepped off the required number ofteeth to rotate the arming ring 137 to armed position. Should the speedof rotation of the reel diminish from the speed required to extend theplungers y77 into engagement with the clutch ring 136, rotation of theclutch ring and idler pinion thereon is interrupted and the arming ring137 is no longer moved in the direction of the armed position.

Assuming that the fuze has been armed in the manner heretofore describedduring the fall of the vmine from the plane, the subsequent impact ofthe mine with land or water, as the case may be, is effective toactivate the inertia responsive switch 105 for closing the circuit tothe primer whereupon the powder train 50 is ignited. If by chance themine rests upon land or within such shallow Iwater as to permit itsrecovery by the enemy, the powder train 50 continues to burn to ignitethe booster 112 whereupon the mine is exploded in an ob'- vious manner.However, if the mine has fallen within water exceeding a predetermineddepth, during the in terval of the burning of the delay element 50 themine will have sunk suiciently within the water to cause'the surroundingpressure thereof when applied to the inner surface of the bellows 41 toexpand the bellows for shifting the shaft section 43 to the positionindicated in Fig. 3 whereupon the section 49 of the powder train thereinis moved from alignment with the powder train 50 and the burning 'of thetrain is interrupted. As the y powder train is extinguished, thefunction of the fuze is completed and the remaining controls of the mineoperate as usual in response to the approach of an enemy vessel.

Obviously many'modications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmayA be practiced otherwise than as speciically described.

The invention described herein may be manufactured and used by or forthe Government of the United States of America for govemmental purposeswithout the payment of any royalties thereon or therefor.

' What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

l. A fuze for an aerially launched underwater ground mine adapted toselectively distinguish between the landing of the mine upon `land or inwater exceeding a pre-l determined depth, including, in combination, ahousing adapted for mounting lwithin the casing of the mine, Va powdertrain arranged within said housing, a source of electrical energy, anelectro-responsive primer adapted when energized to effect the burningof said train, a booster charge disposed for being ignited by said trainlto effect the exploding of said mine, means responsive to the impact ofthe mine falling either upon land or water for energizing said primerfrom said source, and pressure responsive means operatively connected tosaid train for interrupting the burning thereof when the mine sinks to apredetermined depth within a body of water.

2. A fuze for an underwater ground mine adapted to be released lfrom aplane in flight including, in combina` tion, a housing adapted for beingreceived into the side wall of the mine, a booster charge arrangedwithin said housing and adapted when energized to effect the explosionof said mine, means for igniting said charge including a powder trainoperatively connected therewith', an electro-responsiveprimeroperatively connected to Said train for eifectin g the burning of thetrain when the primer is energized, an arming ring having therein asegment of said train and rotatable from an initial position to an armedposition for aligning said segment with the train, means for rotatingsaid ring responsive to the fall .of the mine from the plane, a circuitincluding an inertia responsive switch for energizing said primer uponimpact of the mine with either land or water, and a pressure responsiveelement operatively connected to said train to interrupt the burning ofthe train when the mine sinks to a predetermined ,depth within a body ofwater.

3. A fuze of the character disclosed for use in an aerially launchedunderwater gro-und mine and including, in combination, a housing adaptedfor mounting within the .casing of the mine, a reel arranged forrotation in said housing, a length of wire arranged about said reel andadapted when rapidly drawn therefrom to apply a high rate .of rotationthereto, a plurality of inertia responsive elements operativelyassociated with said reel and adapted in respense to a predeterminedrate of rotation thereof to be centrifugally extended therefrom, abooster charge arranged in said housing and adapted when ignited toeffect the explosion of said mine, a powder train arranged for ignitingsaid charge, means including an electro-responsive primer adapted whenenergized to efect the burning of said train, an arming ring arranged tobe engaged by said elements and rotated by the reel when the elementsare extended, said ring having therein a section of said train forcompleting the train upon predetermined rotaryl movement of the ring,means including an inertia responsive switch for energizing said primerupon impact of the m-ine with either land or water, and a pressureresponsive element operatively connected to said train and arranged Itointerrupt the burning of the train when the mine sinks to apredetermined depth within a body of water.

4. A fuze for use in an aerially launched underwater ground mine of thecharacter disclosed and adapted to selectively distinguish 'between thelanding of the mine upon land or in water exceeding a predetermineddepth, including, in combination, a housing adapted for mounting withinthe casingof the mine, a reel arranged-for rotation in said housing, alength of wire arranged about said reel and adapted-when rapidly drawntherefrom-to apply a high rate of rotation thereto, an arming ring, aplurality of inertia responsive elements carried by Vthe Areel andoperatively associated with said ring and adapted in response to apredetermined rate of rotation of the reel to engage said ring forrotation with said reel, a powder train having `a section thereofarranged in said ring and rotatable therewith into alignment with saidtrain, an electro-responsive primer adapted when energized to effect theburning of said train, a booster charge for exploding said mine, saidcharge being disposed in tiring relation with respect yto said train andarranged to be ignited thereby, means including an element responsive tothe impact of the mine falling either upon land or water for energizingsaid primer, and pressure responsive means operatively connected to saidtrain for interrupting the burning of the train when the mine sinks topredetermined depth within a ,body of water.

5. A mine fuze of the character disclosed adapted to selectivelydistinguish between the landing of an aeriaily launched mine upon landor in water exceeding a predetermined depth including, in combination, ahousing adapted for mounting within the casing of the mine, a reelrotatably arranged in said housing, a length of wire arranged about saidreel and having one end thereof extending outwardly through an openingin said housing and through which the wire may be drawn rapidly fromsaid reel for applying a predetermined rate of rotation thereto, atubular resilient member arranged wit-hin said openingfand having saidwire extended therethrough, the other-'end of said wire having thereon aplug adapted for being drawn into saidtubular member to close the open-Cil ing therein, centrifugally responsive elements operativelyassociated with said reel and adapted in response to a predeterrm'nedrate of rotation thereof to be extended outwardly from said reel, abooster charge arranged in 4said housing and adapted when ignited toeffect the explosion of said mine, a powder train arranged for ignitingsaid charge, a power source, means including a primer effective whenenergized to ignite said train, an arming ring arranged to be `engagedby said elements when yextended and coupled thereby to said reel forrotation therewith, said arming ring having therein a section of saidtrain arranged to be brought into alignment therewith upon predeterminedrotary movement of the ring, means including an inertia responsiveswitch for energizing said primer from said Asource upon impact of themine with either land or water, and a pressure responsive elementoperatively connected to said powder train and arranged to interrupt thepowder train when the mine sinks within a body of water below saidpredetermined depth.

6. A mine fuze of the character disclosed adapted to selectivelydistinguish between the landing of an laerially launched mine upon landor in water exceeding a predetermined depth including, in combination, ahousing adapted for mounting within the casing of the mine, a reelrotatably arranged in said housing, a length of wire arranged about saidreel and adapted when rapidly withdrawn therefrom to apply a high rateof rotation to said reel, inertia responsive elements operativelyassociated with said reel and adapted in response to a predeterminedrate of rotation of said reel to be centrifugally extended therefrom, abooster charge arranged in said housing and adapted when ignited toeffect the explosion of said mine, a powder'train arranged rfor`igniting said charge, a power source, means including a primereffective when energized to ignite said train, an VVarming ring arrangedto be engaged by said elements when extended and coupled thereby to saidreel for krotary movement therewith, said ring having therein a sectionof said train arranged to `be brought into alignment with the train uponpredetermined rotary movement of the ring, means including an inertiaresponsive switch for energizing said primer from said source uponimpact Yof the mine with either land or water, and a pressure responsiveelement operatively connected yto the powder train for interrupting thepowder train when the mine sinks within a body of water ybelow saidpredetermineddepth.

7. A fuze fortan aerially launched underwater ground mine including, incombination, Aa housing, lan explosive arranged in said housing andadapted ,when ignited to effect the explosion of said mine, a primer, aninitially interrupted `powder train connecting lsaid primer to saidcharge, the primer being adapted when detonated to elfect the burningofsaid train, means resPQDSive tothe fall of the mine from the plane forcompleting ,said initially interrupted powder trainthereby to arm the fuze, means .responsive to the impactrof the mine with land or water lfordetonating said primer, and pressure responsive means for interruptingthe burning of saidtrain when the minesinks 4to ,avpredetermineddepthwithin a body of water.

8. A mine fuze of the character disclosed adaptedrto selectivelydistinguish between thelandingof anraerirally launched mine upon landorin water vexceeding a predetermined depth including,lin combination, lahousing adapted .for mounting within the casing of the mine, a boostercharge arranged insaid housing 4and adapted when ignited .to effect theexplosion of Asaid mine, La primer for igniting rsaidboostercharge whendetonated, a fuze train interposed between said primer and charge, anarming ring interposed in said fuze trainand having a tra-in sectionadapted upon predetermined movement of the ring to bemoved from a safeposition to anarmed position in which the section is alignedwiththetrain, a reel rotatably arranged intsaid housing, a length ofwire arranged about said reel and adapted when rapidly withdrawntherefrom to apply a high rate of rotation to said reel, a plurality ofinertia responsive elements operatively associated with said reel andarranged to engage -for launching from a plane in flight including, incombination, a housing having an opening therein, a shaft constructedand arranged in said housing for axial movement in a plane substantiallyperpendicular tothe axis of said opening, means for applying axialmovement to said shaft including a pressure responsive element opera- Iconnected to said charge, a segment of said train rotattively connectedthereto, a reel arranged for rotation about said shaft, a length of wirearranged about said reel and having one end thereof extending throughsaid opening through which the wire may be rapidly withdrawn from saidreelfor applying a high rate of rota-` tion thereto, an arming n'ng, aninertia responsive clutch operatively connecting said ring to said reeland adapted in response to a predetermined rate of rotation of thelatter to effect the rotation of said arming ring, a booster chargearranged for exploding said mine when ignited, a power source, a fuzedelay element, an electroresponsive primer adapted when energized toeiect the burning of said delay element, an initially interrupted powdertrain ignitable by said delay element and operatively able by saidarming ring from an initial position to an armed position in alignmentwith said train, an inertia responsive switch for energizing said primerfrom said source upon impact of the mine with land or water, and meanscarried by said shaft and effective to interrupt the burning of saidtrain as the shaft moves in response to a predetermined pressure appliedto said pressure responsive element.

10. A Ifuze as in claim 9 further characterized by provision of areduction gear between said clutch and arming ring.

11. A. mine fuze of the character disclosed for seltively distinguishingbetween fthe landing of an aerially launched mine on land or in water ofa predetermined depth comprising, in combination, an explosive charge,

inertia respons-ive means operable in response to impact of the minewith land or water, means responsive to said inertia means for tiringsaid charge in predetermined time delayed relation to said impact of themine, and hydrostatic means for disabling said tiring means when themine sinks within a body of water to said predetermined depth. l

References Cited in the le of this patent UNITED STATES PATENTS1,295,097 Anderson Feb. Y25, 1919 FOREIGN PATENTS 2,706 Great Britain of1911

